CHAPTER IL: 
HOW DID THE BIRDS FIRST FLY, PERHAPS ? 
Nature seems rarely surprised in the demands 
made of her. She is usually well up to the emer- 
gency, and often seems to be looking ahead. 
The great instrument of dry land invasion was the 
backbone, and this was developed in the water; and 
the great instrument of vertebrate invasion of the 
“upper deep” was the wing, largely developed, per- 
haps, before its owners made any attempts at flutter- 
ing up. 
The wing as we see it now is much modified by 
the growth of feathers and its adaptation to flight by 
them, but there were reptiles that walked in an upright 
position and exhibited many birdlike characteristics 
before the dawn of the flight quill. 
From the structure of the skeleton it is the opin- 
ion of some eminent naturalists that birds not only 
walked uprightly and hopped bipedally in trees before 
they flew, but that they flew before they had wing 
feathers ; and of many others think that they at least 
crawled about trees before they flew, as the frequent 
presence of wing claws yet indicates, and as a few in- 
stances of modern young birds crawling and climbing 
by these claws hint. 
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